Amateur Telescope Making & other do it yourself projects

ATM & other do it yourself projects

Fixing Extra Shoe to SkyWatcher 200P, with screws!

Hi All

After some discussion with Andy T on the benefits of a laser pointer for finding objects, I decided to get one of these. The laser and the bracket are yet to arrive but the extra shoe needed to mount it to the tube, ordered from Harrison Telescopes, arrived in 3 days. This is now fitted with the M4 countersunk screws and black nuts supplied. I will outline the method I used and tools needed, for comparison with Andy’s adhesive-based method (10 March) so you can decide which to use.

1. Make sure you think hard before you decide on the location; drilled holes are permanent. I placed mine about 20mm from the finder-scope shoe, to match the gap between it and the focuser base.

Tools needed

2. Attach masking tape to the area where it is to be attached.

3. Rest the tube horizontal up against a firm support with the focuser aperture above the area to be drilled, to prevent swarf/cuttings getting in. Also, I put newspaper directly under the drilling area to catch any cuttings and masking tape along the inner edge of the stiffener on the end of the tube. Time taken in preparation is well worth it. See the photo below. I would not advise doing this task with the tube in the mount.

4. Mark lines on the masking tape and use the shoe as a template to mark the locations of the two holes.

5. Check that the holes will clear the reinforcing plate (if fitted) inside the tube used for the finder-scope shoe.

6. Tubes are made of thin steel, work-hardened by the rolling process, so sharp drills are essential. Start with a small size drill, say 2.5mm and work up, in steps of 0.5mm, to 4mm diameter. This minimises the force needed to break through initially and subsequently to increase the hole size. Small drills break easily so do not apply too much force, have only a short length of drill protruding from the chuck and try to align the drill radially to the tube.To make sure the drill chuck could not touch and mark the tube, I pushed a rubber tap washer onto the drill, masking tape alone is not thick enough. Make sure you are in a comfortable position and able to control the pressure applied by the drill.

7. After drilling one hole, loosely attach the shoe and check the marked location of the 2nd hole.

8. If the 2nd screw will not insert, increase the hole size of one hole, or both if needed, to 4.5mm. Mine were fine with 4mm diameter.

9. Remove masking tape and the paper inside the tube and attach the shoe. I used a small spanner (shown in photo) to hold the nuts while tightening. Take care not to shear the screws as they have a small cross-section and not to scratch the black paint inside the tube.

Hold nut with small spanner
Job done

Once the bracket and laser arrive I will post a photo of the finished assembly, soon I hope!

Paul

Adding Sky Watcher finder scope style mounting shoes to Orion UK 10″ Dobsonian telescope

My trusty and well used Orion 10″ Dobsonian telescope does not have Sky Watcher style finder scope shoes – a nuisance as I would like to use a finder scope with it and also attach my heated laser finder device which has Sky Watcher style finder bracket.

So today out came the glue gun and I attached two finder shoes to the tube. If the glue gun turns off with time not to be strong enough then I will bolt them on but hopefully this won’t be needed as not much weight on them.

The other advantage of using the glue gun initially is that I can change position of the finder shoes if it turns out they are not in the best place in practice.

Andy

I chose a rather cold day to do this!

OK so in the next picture it looks a mess. However, once the glue has cooled I will then be able to tidy it up and I would rather put a bit more glue on so that my stuff does not fall off the scope, including my bargain from the Practical Astronomy Show – right angled 9×50 finder scope with illuminated eyepiece for only £45, which I bought especially to put on this scope!

 

Video electronic eyepiece again

Here are another couple of snapshots from the video electronic eyepiece screen, (see https://roslistonastronomy.uk/video-electronic-eyepiece-image-intensifier) this time the M41 cluster as well as M42. It is quite difficult to get a decent snapshot with a camera due to it being tricky to get the exposure right.  I have also found that for visual observing in the dark, it is best to turn down the brightness and contrast as far as it will go on the monitor.

It is probably worth-while comparing these with the processed images from from a few minutes exposure with EXACTLY the same kit (plus a PC, of course) from EXACTLY the same location. (the window-sill). Both methods have their place, of course! Perhaps unsurprisingly, the clusters come out best.

 

By the way, given some recent discussions, the M42 image is a composite of 4 exposures

If the cap fits …….

A couple of days ago the sun was shining nicely (that’s the big yellow thing that hangs in the sky occasionally) so I though I would try some more solar observing. I was just slewing my scope tound when it suddenly occurred to me that my guide camera was about to get fried as there was no cap on the guide scope.

I looked around my junk box for an old binocular cap but of course none of them fitted.

Rather than going into full-blown Blue Peter mode I thought I’d look on eBay for a cap, and I came up with this. It’s like a DSLR lens cap but slightly smaller (52mm)

https://www.ebay.co.uk/itm/Lens-Cap-52mm-Lens-Camera-Cover-Lens-Cap-Cap-Protection-rg-UK-lens-cap/202031877076?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

It works a treat and was only £1.79 from a UK source. It clips in very firmly and even has a string attached so you cant lose it

Video electronic eyepiece/image intensifier

Imaging is imaging, usually with a computer to process said images later.

Visual observing is when you look through an eyepiece and get an “instant” view.

As soon as you start to use electronic assistance such as an image intensifier the distinction between these two gets a bit blurred.

The PD camera produces a video output that you can feed directly into a video monitor and get an “instant” or “near instant” view, depending on what integration time you use. No computer is needed.

So here is a slant on that theme. I purchased a 5″ video monitor for the princely sum of £16.99. It runs off 5V, so I also purchased a 12V-5V converter for another couple of pounds. I then coupled it to the PD camera like this:

 

Here are a couple of snapshots of the “instant” result of the Orion nebula using the window-sill 80mm refractor. The first one is as it comes, the second with a UHC filter.

 

Not a patch on proper imaging, of course, but interesting!

I could easily see the Flame nebula like this, and I fancied I could (maybe) also see the Horsehead – – -! (From the window-sill, of course!)

Making our own image intensified eyepieces

Making our own image intensified eyepieces

Andrew & Damian

 

This entry is a copy of an entry made in November 2009.

The commercial versions of these eyepieces cost £1500 ($2000) upwards…….here we describe how we made one for £50 ($80) plus some spare SLR lens/extension tubes lying around the house.

The main differences that we are aware of between the commercial versions and ours are:-

(i) Theirs has a higher resolution – not that we noticed at the eyepiece!

(ii) Ours has more distortion of the field – oh well you can’t have everything!

(iii) Theirs are a lot lighter…no getting away from that – our version requires a sturdy telescope/mount and 2 inch focuser.

What we are less sure of is:-

(i) Any difference in brightness? Possibly but the image intensifier we used is a 3 stage generation 1 intensifier that gives pretty bright images

(ii) Fun level – ours delivers on the fun side

(iii) Both image intensifiers can be used with an SLR lens without the scope – probably the best bit

(iv) Ours gives you the enjoyment and sense of achievement of having made it yourself

(v) Price difference – this is one aspect of ATM where there is still a really big difference in price between the ATM version and the commercial version!

Please note we accept no liability for damage or injury incurred from following our instructions (its just what we did) and we make no guarantee that this will work for you. Please let us know if you find a better way of constructing your eyepiece so we can update this website. You will need to source components – a difference image intensifier should work but you will need to modify the instructions. Plus – please note neither of us have had a chance to compare our version with the commercial versions.

We hope you have great fun making your image intensified eyepiece!

The two files below are both PDF files:

Image-Intensifier-Info-Instructions-Nov-2009

Instructions-making-image-intensified-eyepiece-2009

Andy & Damian

 

DIY Polar Scope Illuminator for EQ5 Mount

I recently bought a 2nd hand Sky-Watcher Explorer 200P on an EQ-5 mount off AstroBuySell UK.com and was pleased to discover that it came with a polar scope. For the unitiated, these are used for aligning the polar axis (that’s the extra one that alt-az mounts don’t have) to the north celestial pole so that objects can be tracked by moving the scope in the Right Ascension (RA) plane only. Alignment requires sighting Polaris through the polar scope so that it aligns with a specially engraved reticule inside the polar scope eyepiece. The problem is that when its dark, the reticule markings cannot be seen so have to artificially illuminated (but not too much otherwise it swamps the stars!)…by a polar scope illuminator. Of course, you can buy one at £23 but reviews of them were very mixed so I researched how to make one, after all it’s only a fancy dim torch how difficult can it be?

The description below is really a prototype (with help from utube) as I tried various options while making it. The bought ones fit on the eyepiece but mine fits on the inside the hole in the mount at the ‘objective’ end.

Parts Needed – plastic

From Screwfix, Wickes or Discount Store, Swadlincote

  • 32mm plastic equal tee with compression joints –– about £3.
  • 32mm socket plug – £1.20
  • 40mm socket plug – £1.20
  • 32mm PVC pipe – £2.40 for 3m – we need about 250mm! Try to find an off-cut.

Parts Needed – electrical

From RS Potts Babbington Lane, Derby

  • Small red LED
  • Small rocker switch
  • AA double battery holder
  • 1W rated resistor
  • Small connectors (3)
  • Low voltage cable
  • Insulating tape, or earth wire insulation
  • M4 screw, nut and washer
  • 2 x AA batteries

I had some of these already but I bought the LED, resistor and battery holder for a total of 94p.

Method – refer to photos

Cut the pipe into 2 pieces: 100mm for battery/switch compartment and 50mm for inserting into mount. The longer piece and the branch stub of the tee need to be cut to fit the rocker switch, making sure it faces downwards for easy access when looking through the polar scope. Cut away the flange of the 40mm plug to form a neat end for the battery compartment.

For my mount, I needed to reduce the diameter with a rasp/coarse emery for it to fit snugly inside the hole in the mount. This was a pain by hand but would take only minutes in a lathe.

I made a support (12mm x 150mm but length depends on your mount) for the wires to the LED from a 150mm length of pipe and bolted it to the bottom stub of the tee with M4 screw/nut. Tape wires to the support to keep them out of the field of view.

The 32mm plug is just a cap for the top plug when not in use. My photo shows the branch of the tee curving upwards but it’s better to arrange it curving downwards (remember mine is a prototype!).

Wire up the battery compartment, switch, resistor and LED (polarity is important for the LED). Carefully measure the lengths of wire needed to avoid excess. Soldering is better but I used small plastic connectors. Use tape or insulation to cover any bare wire connections.  Fit the batteries and test. If all ok, carefully thread the wired assembly into the tee piece and your ready to try it out. The support and position of the LED may need to adjusted/bent to avoid it shining directly into the polar scope.

You have a polar scope illuminator for about £10. At the next opportunity, I will attempt to take a photo of the view through the polar scope when illuminated and add to this post. Feel free to ask questions. To finish I would like to hear details from anyone who uses a 90 degree viewfinder on their polar scope, its a long way down to the eyepiece without one.

Illuminator Fitted to EQ5 Mount
Finished Assembly
Exploded View

Building a Shed/Observatory in 5 minutes

The one upside of the last few weeks abysmal lack of astro friendly weather is that I’ve finally had the opportunity to put together the time-lapse videos from my shed project. OK- It’s only 5 minutes with the help of time-lapse video- but it was quite a quick build when I actually got the chance to work on it.

One evening last May there was a unanimous perfect forecast from different weather apps and I dutifully set all the gear up for some imaging. Just as we were getting to darkness a thick bank of cloud rolled in. As it was not forecast, I decided to hang on for the sky to clear, and instead spent the next hour looking round the garden working out how I could have a more permanent set up with all of the advantages it gives. And no- the sky didn’t clear that night…

Looking about the internet there are some amazing creations- both home-made and purchased- but these were all well beyond my available resources for this project in either time or money. Besides keeping costs down, I wanted the following:

–          Really small footprint.

–          I didn’t want it to look like an observatory (which is much too grand a word anyway for this shed).

–          If I wanted to bring my mount out to a club evening or dark site, I didn’t want it to be any more hassle than taking the mount and scope out of the garage is.

So:

–          I used an 7’x5’ apex shed design. This has the disadvantage of limiting the view where the apexes are- but my views are restricted in those directions anyway- and with the smaller roof panels I can move them manually and drop them down the side walls.

–          Upside-down guttering is used to seal the gap at the top between the panels.

–          No pier- the tripod sits on bricks that come through the shed floor so I don’t cause vibrations when I’m walking around.

–          The roof panels slide off on fixed castors fitted to the shed walls (although in practice the tower bolts catch on the sides and it’s more of a lift than a slide).

–          The electrics are in a ventilated plastic storage box to keep them away from moisture. I run an outdoor cable from the garage when it’s in use. I’m using a Nevada power supply which has been a lot less hassle than using a battery, and I can’t prove it, but I think the mount is running better.

Overall, I’m pretty pleased with it- it only takes a couple of minutes to open the roof, the polar alignment seems to be pretty much spot on each time I check it (despite not having a pier) and my setup time to when I start the first sub has dropped from an hour to around twenty minutes or so. Most of this time is to align, frame and focus.

The shed came from Tiger Sheds and seems to be of reasonable quality. The weight of the roof panels was heavier than I had expected (when I was checking out the design I didn’t allow for the weight of the roof felt- blimey it’s heavy!!!) and I was thinking about ways to overcome this. But I’ve got used to the technique to move the panels, and it has stood up really well to some very wet and windy weather over the last few weeks. For now I’m inclined to leave it as it is. It’s also pretty snug in there. I never intended to use it for observing, but if I ever changed my mind about that I’d probably need to start again because space around the scope is pretty limited and alignment often involves a short stepladder and hanging off walls…

It will just about take a 1200mm Newt OTA, but with that one it is really cosy.

It isn’t quite finished yet- I’m in the process of adding some shelving, I need to improve the ventilation (I’m looking into solar powered fans, but failing that I’ll just put some vents in) and I need to lag the walls to help keep the temperature more stable.

So, if anyone is thinking about a more permanent setup, but is concerned about the cost and effort involved, it needn’t be an architectural masterpiece. The basic shed was £320 and with the materials for the base and other odds and sods I’m probably a little north of £500 for the whole project. Which will hopefully allow me to be a little more spontaneous with imaging. Or at least have wasted less time when ‘secret’ clouds come rolling in…

Hope you enjoy the video (speaking of which- this was partly put together with Videopad as recommended at a RAG meeting earlier in the year- I can second that recommendation! 😊).

Solargraphs – Summer>Winter Solstice 2018

All from Baked Bean cans within a 10 mile radius, using Ilford Multigrade B&W paper. Scanned and played with in Photoshop.

Andy’s first one, slightly different angle to his usual version.

And his second – massive amounts of water damage (was still a few mm of rain in the bottom of the can), but love the effect it’s created. This is his usual angle (so can be compared to previous attempts). Can just make out the house bottom right of centre and the tree to the left.

Mine, screwed to the house, SSE facing.

Sister’s from her new home. Was surprised at the very upper sun trace, but it can be matched to my own above. Thought at first it must have moved or have been a reflection from the inside top of the can. The cans are painted black inside and any movement would have created a double image of the houses – there isn’t anything to suggest that.

One I made up for a lady at my new workplace.

Damian